Seeking advice on filling cracks

Re: Seeking advice on filling cracks

David Hammond, in Powder Springs GA

>I'm still learning about this crack filling, but I'll pass on what little I know. I've used the soot and sawdust, CA mixture Terry advocates, and this works pretty well for small stuff, but not as well on large cracks like you've got. I've recently used some 5-minute, two part epoxy, mixed with black acrylic paint powder, to fill some cracks and it worked wonderfully - I could shape it, and work it with sandpaper and files, and as of now, the cracks I filled look great. I'm also looking into West System Epoxy, and using this huge line of boatbuilding epoxy, with the black powder, for a high strength, workable crack filler, but I haven't tried this yet.

My .02

David Hammond

My Dad & Me, Inc.

Re: Seeking advice on filling cracks

Doug Trembath

>Lyn, I have used a lot of fillers, from crushed Turquoise to brass filings and now to coffee grounds. My major concern with these materials is the archival question, or how long will it look like this?

I've looked at so many options on this with inconsistent results, much as I'm sure you have.

Absent any crystal ball, I have been leaning toward the more advanced West Systems epoxies. Many ways to condition it, both structurally and aesthetically.

I'm interested to read the thoughts on this one.

Doug Trembath

Studio in the Woods

I have had good success with black epoxy.

Dave Smith, Longview, WA

>Hi Lyn,

I feel a little sheepish suggesting a process to such an experienced turner as you. I have been using a filler of 30 minute epoxy colored with black acrylic paint. Acrylic colored epoxy has been used to fill voids in mesquite lumber for a long time. It takes several applications to fill large deep gaps. I use a propane torch to produce CO2 which causes the epoxy to off gas or bring the bubbles to the surface. A vacuum bag can also be used to degas the epoxy. I have tried tape to seal the bottom of cracks but it tends to leak. Now I use a thin piece of cardboard such as business cards attached to the bottom with yellow glue. The glue ensures a good seal and eliminates leakage. Depending on the geometry of the piece it may take multiple applications of epoxy to completely fill a void. I have found that epoxy will penetrate very well but here are always areas that don't get completely filled. After rough turning the piece unfilled areas that are revealed can be filled.

Good luck.

Dave Smith

Typing instead of turning in Longview, WA.

Re: Seeking advice on filling cracks

Dale Cook

>On work that I've turned that had black in it such as splalted maple and also had cracks or voids that needed filling I've hammered a piece of charcoal in a bag to a fine powder and mixed with epoxy.

Re: Seeking advice on filling cracks

Frank Joseph- mantua nj

>Take a trick from fly tiers. mix Testers hobby paint with 5 mi expoxy. you can get it in a lot of collors. it mixes well and bonds very well. fly tiers us it for jigs and heads on flys.

I used it on a ceader vase I turned monday worked very well,

Re: Seeking advice on filling cracks

John Lucas

>Lynn

I use 2 hour epoxy to fill large cracks. My understanding is that this is stronger than the 5 minute. I don't know for sure just heard that somewhere and in my limited experience glueing 2 things together it seems stronger. I mix it with crushed black chalk but have also used copier toner and India Ink.

To get real penetration of small cracks try System 3 mirror coat from Woodcraft. This stuff will actually penetrate the end grain of softer woods. It's thermal setting and gets really thin as it sets. I use India Ink for this because powders make it thicker and it won't penetrate as well. It becomes so viscous that it's hard to control. It will run anywhere it can including through tiny holes and get all over your work bench. trust me on this. It's reallly hard to sand off your workbench. Fortunately I had recently waxed the top so most of it came off.

Re: Seeking advice on filling cracks

TDaniel

>Lyn, as some have already said, I use soot and fine sanding dust for the smaller cracks. Pack it in and then wet it with thin CA. I find it better to contrast the wood rather than try to match it. Sometimes a small crack will look like a crack so I enlarge the crack a little with the tip of my pocket knife. For larger cracks I use epoxy with dust and sometimes soot. It only takes a small amount of soot to turn the stuff all black. If there is only one crack in a vessel I will enlarge it, if necessary, and fill it with one of the above and then lace it with wet rawhide strips. I never use the rawhide if there is more than one crack. I am still searching for the best way to deal with really big voids. On a recent piece after filling a large void I scratched enough filler off and mixed some brass filings with the epoxy and wiped that over the area, then sanded smooth. On this particular piece of wood the brass really looked good. On the other hand, every time that I have tried to match the color of the wood it has looked like a piece of wood that should have been thrown away.

TD

Re: Seeking advice on filling cracks

Bill Grumbine, Kutztown PA

>Hi Lyn

I have used leftover boat building epoxy mixed with stove black, which is essentially the same as soot in a can. The advantage to the stuff I am using is that it is fairly thin, and so will run into the cracks fairly easily. However, its big disadvantage is that it is fairly thin, so it will run out of the cracks fairly easily! Still, if you can set your piece up and use a dam here and there made of modeling clay, you can fill cracks that will end up looking very nice when done, as you can get the stuff to polish up pretty shiny.

I bought the stuff by the gallon when I built my boat, but you can buy sample kits which will contain resin and various hardeners (for different times) for about $10.00 $12.00. I bought mine from Raka at www.raka.com.

Bill

Re: Seeking advice on filling cracks

Dick Hines

>On rose wood I thin I would use instens offee. That would :led" in with the color of the wood. ButI have used brass fileings and other things if I want contrast.

What ever you use be sure o pack it in until you can't get any more in the crack. Thyen use hin CA . If the cracks deep I will put in more than one layer. Don't shoot it with accerarater because of the white stuff it causes.

Post a picture.

Re: Seeking advice on filling cracks

John Steger

>Golfsmith has A 16 hour black epoxy (shafting epoxy). It comes in the dual syringe type dispenser. If it can stand up to a 3 wood I guess it would work on a bowl.

Re: Seeking advice on filling cracks

Duane C.Leach

>Hi Lyn

If the cracks are worring you so much you might try cuting the chunk down. See if you can make something smaller without cracks. Try rough turning before filling cracks. The deeper the cracks the harder it is to get the filler to the bottom of the crack. Make for sure the cracks havenot weakened the wood so much that it will fly apart when turning.

Good luck and post a picture before and after finish.

Re: Seeking advice on filling cracks

Scott Thorburn

>Lyn, Most people are suggesting Epoxy with some sort or coloring. I often use this method. I prefer inks to color . Only a little is needed and it doesn't affect the thickness of the epoxy.

One other method you can try is try coloring Polyall and pouring that into the cracks. The advantage with Poly all is it is very thin and will pour into and fill all cracks, and it also sets up quickly ( 3 min). You would need a dam if any of the cracks go all the way through. For the dam I would suggest the modeling clay and or Duct tape. I think for the rosewood I would go for a very contrasting filler maybe gold ink.

West System

Bob Hackett

>The big advantage this product has it that it is in fact a system.They have additives for most every application from adding structural strength to fairing with"micro ballons" and the instructions to go with the products.

The one thing that worries me about adding things like ink or soot to epoxy is the chance of compromising the strength of the resin once it sets.West System offers tech support and will steer you in the right direction as far as thinning for penetration in wood or changing the color of the resin by adding anything to it.

The only other epoxy product I know of that comes close for tech support would be System 3.I`ve heard of local boatbuilders using off brand products who were told to refer to the West System or System 3 instructions when they encountered problems.

When my brother Bill and I worked together to make an urn for my father`s ashes from a small cocobolo log we opted to fill voids and checks with epoxy for structural strength and then used the same colored shellac sticks restorers used to fill any small voids.Bill has since used the epoxy for strength below and shellac over on other projects to good effect.I believe he even used rough sanded wire embedded in the resin in larger intersecting cracks to add strength.

The thing to remember is to rough the surface of the expoxy for a good bond before using the shellac sticks.Epoxy is also heat sensitive so be cafeful with the burn in knife.

Hope this helps.

Mainely,Bob

Re: Seeking advice on filling cracks

Bill Hale, Woodspinner

>Lyn

I woould use some of the finer turnings and run them through a household blender. I got mine at a yard sale. Tape the inside of the bowl and pack in the fines from the outside, layer if needed. Do not fill to the top of the void and use thin CA on each layer. When you get within a 1/16 in. of the outside Dia. inlay what ever you like. My thought on a fill for this wood would be a copper and turquoise fill with CA. You can buy a copper material at hobby shops that is in flake form and very thin. Just my thinking!

Be sure to post a PIC when you get done.

Good turning and above all be safe

Bill

Re: Seeking advice on filling cracks

Joe Fleming

>Lyn,

I will start by echoing Duane's suggestion. Why turn a cracked piece of wood to end up with a cracked bowl? Big doesn't make it intrinsically more valuable, but cracks will make it less so. I have a stash of Brazilian rosewood spindle stock that will become a chess set one day. Small items are precious and beautiful too. So, make a box, make a sphere, or make a pair of candlesticks. Make a few small bowls to get the flame.

Having said that, don't use CA. CA is brittle and has been known to fail over time. Since you describe gaps that need filling, CA is NOT a good gap-filling adhesive. Rosewood is also oily making adhesion difficult. I would use epoxy (I like West Systems products). Most any of the coloring suggestions previously mentioned are good. I would experiment with several for effect before pouring on that wood, however. Try making a scrap bowl blank and running the rim side through the table saw to create some artificial gaps to fill. Turn the bowl and fill as you would if it is the real thing. Several kerfs in one bowl will yield several trial sites.

Good luck,

Joe Fleming - San Diego

Re: Black Lacquer

Ben Aragon

>Lyn,

I used black lacquer on piece of wormy chestnut to build a small table. I poured the lacquer over the tabletop and let it dry completely. I then ran it threw the planer and sanded. The voids were filled nicely and the top had a clear lacquer finished added, really nice. I�m not sure how well this will work on a bowl. I would test this process on some other not so valuable piece of wood. The lacquer I used was not thinned but it is still very thin and you will have to come up with a way to keep it from leaking out of the cracks. Black lacquer will finish like the hook of a Cadillac. I did not invent this.

Ben

Re: Seeking advice on filling cracks

Russ

>You have a lot of suggestions already, but here is what I would do with it. They may have already been made.

First, I have never had any success with filling cracks before turning anything. However, I tell myself that squirting thin CA into them will help hold the wood together and keep them from propogating any farther. I have no idea if the CA actually does anything or not, but it makes me feel better for having done something.

Then I would turn it to final shape and ready to sand on the outside before addressing the cracks. That way, I can see what really needs to be done. If the cracks become a problem before getting it to final shape, I can take care of them as they occurr.

By doing this I will see all of the cracks. Some will have disappeared, and others will be new.

For filling cracks, my preference is always "black". I would use the epoxy and charcoal on the larger ones; Medium CA followed by rubbing with an artists charcoal stick for the smaller ones up to about 1/16"; and wet-sand with medium CA glue or Deft lacquer for the tiny ones if there are too many to treat individually.

Then I would hollow it out and repeat the process on the inside.

The wet-sanding with CA glue or lacquer will make a slurry that will fill the small cracks, and fill in around and harden the larger patches. It isn't much different from wet-sanding with anything else.

If wet-sanding with CA glue is something new and different, practice on a scrap piece of wood. Get some sanding dust on the surface before starting. Regular sandpaper is OK. Use it by hand or power or whatever it takes, and don't spin anything fast enough to fling the glue. Add the glue after the movement has started, if you can; if you can't do that, all that is lost is some time; and don't stop until AFTER the glue has cured.

My opinion on using the coffee grounds and CA glue is that, regardless of the color or size of the coffee, it looks like bark. It has the texture and coloring of bark. It is best used to repair voids in and around bark inclusions, repair bark on a natural edge, or to add something that looks like bark where there isn't any. It would look out of place as a filler in a crack in a piece of Rosewood. Again, my opinion.

Bleeding and stain of the CA glues into the surrounding wood shouldn't be a problem with the Rosewood because its natural oils will prevent it from wicking into the surrounding wood.

Re: Seeking advice on filling cracks

William R. Duffield on the Cohansey

>Better than duct tape for the dam is clear plastic packing tape. The adhesive it uses doesn't wick the epoxy or release from reactions with the hardener, the tape releases much more cleanly from the wood after the epoxy has kicked, and you can see through it to better determine when you have poured in enough epoxy to fill the crack.

Also, I prefer West System, and have used it with the black pigment that they sell as a colorant for filling walnut burl, afterwards sawn, rasped and filed and carved, but not turned.

Re: Black Lacquer

Ben

>Boy, I should use a spell checker.

I think I might try this on a bowl.

Does anyone see a problem with this technique?

I plan on pouring the lacquer in the cracks while the blank is still in the rough, let it dry and then turn.

Best Regards,

Ben